Yippee! I have a date!
Thank goodness for sisters! You are lucky to have that resource. Depending on the age of you children maybe you could rely on friends of the kids to take the kids for an "overnight" after your sister leaves. Neighbors to take the kids during the day. I feel for you as I raised my son by myself for a few years and when I was sick it was hard to keep him happy. Lots of videos and Easy Mac! Make things easy for yourself, easy snacks, have the laundry all done, beds made and everything before. Good luck!